The Oxford Comma

When you have a series ending with a conjunction, you need to use the serial or Oxford comma. (He talked about the economy, loss of jobs, and the cash-for-clunkers program.) Note that this comma is not used in journalism.

PS: If you don’t like the Oxford comma or if you think that punctuation can be sacrificed for love, you might enjoy this song, “Oxford Comma” by Vampire Weekend. (Be warned, however, that it contains some “language.”)

Commas You Can Do Without

Although they are more important than the song’s opening line might suggest, there are, however, times when you don’t need a comma.

Writers often think titled and entitled need to be followed by a comma, but, as this old Chicago FAQ points out, that would mean that the title of the book is not necessary to the sentence. If you were to use a comma after titled in the sentence “O.J. Simpson agreed to write a book titled, If I Did It, in which he explained how he would have committed the murders” it would mean the sentence could read “O.J. Simpson agreed to write a book titled in which he explained…”

You also don’t use a comma with a compound predicate, because both verbs have the same subject: Only the Austrian approach offers a different paradigm and allows us to see just what is wrong with the “aggregate demand” view of the economy. See Chicago 6.34 for more examples and exceptions.

Apostrophe S

Plurals are not formed with an apostrophe unless it’s being used to disambiguate. Plurals of numerals, abbreviations, and letters are usually formed by just adding an s (Chicago 7.14).

When talking about decades, it’s the 1920s and 1940s. (The confusion comes from the fact that you make the plural of 0 and 1 as 0’s and 1’s, but that is to distinguish them from the letters — Os (oh es) and ls (el es).)

When you are using abbreviations like “PhD,” just add an s to make it plural: She told the GIs she had two PhDs.
Otherwise it is a possessive: The PhD’s diploma was framed on the wall.

HOWEVER, if your abbreviation has two or more periods in it, you should in fact use an apostrophe as well as an s: She had two Ph.D.’s. (Chicago recommends using PhD rather than Ph.D.)

The Colon

To quote Chicago,

A colon introduces an element or a series of elements illustrating or amplifying what has preceded the colon. Between independent clauses it functions much like a semicolon, and in some cases either mark may work as well as the other; use a colon sparingly, however, and only to emphasize that the second clause illustrates or amplifies the first. (Chicago 6.59)

Please note that although in the above description the manual is not explicit about it, the introductory phrase must be an independent clause.

Wrong: Mises wrote: “Man acts.”

Right: Mises wrote, “Man acts.”

Right: Mises wrote the following: “Man acts.”

You only have a capital letter after a colon if it is introducing two or more sentences.

The professor gave two examples: shortages and gluts.

The professor gave two examples: Price controls that set price ceilings too low cause shortages. Price controls that set price floors too high cause gluts.

Don’t use a colon after terms such as for example and namely.

He claims, for example, that…

A colon is not necessary when introducing quoted material.

It is often used after thus or the following (She quoted the following in her article: “If…”) (Chicago 13.17). If the quoted material is preceded by verbs such as wrote, said, etc., use a comma.

For Your Amusement (and Edification)

And speaking of “language,” you might be interested in this post about the man whose editing style gave us the word bowdlerize.

Is there something you’d like to contribute or see covered in Editing for Liberty? Post a comment! Contributions to “Spot the Error” are especially welcome.